Conventionally, a digital copying machine has been well known in which an original to be copied is read, the read image data is stored in a storage device such as a hard disk, and the image data is output via a network to other printer unit and printed. Also, another digital copying machine has appeared having a multiplicity of functions, in addition to the proper copying function, including a print function of printing out the print data input from an external computer and a facsimile function of receiving the facsimile (FAX) from the public line. The copying machine having such multiple functions is referred to as a multi-function device.
This multi-function device is more intelligent than a single function copying machine or facsimile device, and has high extendability for the future.
The space for installation is reduced with one multi-function device as compared with a plurality of single function devices to provide for multiple functions.
Such multi-function device is required to store unnecessary application programs or the data within the device, although it has high extendability, and needs more memory capacity to be mounted as the specification or function increases.
It is also provided with a large capacity memory device such as a hard disk to store a large amount of data. Further, owing to high functions, the multi-function device needs a complex installation procedure in installing, resulting in a longer installation time, and an enormous amount of documents including an installation procedure manual, or bringing about a necessity to download more data and store it for the online manual.
The multi-function device has an energy saving function of automatically transferring to a sleep state to reduce a consumption power of the device, if not used for a predetermined time.
A cluster system is well known having a clustering function of effecting the print out process or other process at higher rate by connecting a plurality of multi-function devices to a network.
However, since the energy saving function of each device operates asynchronously with the clustering function, there is a case in starting the clustering operation where the number of devices in a standby state is smaller than the number of devices required in the cluster system. In this case, it was required that each device in a sleep state was once activated, and then the clustering operation was started again.
In this way, if the energy saving function provided for each device is effectively performed, the initiation time during the clustering operation is longer, impeding the high speed processing with the cluster system.
On the contrary, in order to place each device in a clustering operable state in a short time, it was required the energy saving function provided for each device might be inactivated, and each device might always be placed in an operable state. Therefore, there was the problem that the energy saving function provided for each device became unavailable.